FOREST STRUCTURE AND FIRE HISTORY AT LAKE ARCADIA, OKLAHOMA COUNTY, OKLAHOMA (1820–2014)

Evidence indicates that the structure of Oklahoma Cross Timbers forests are in transition due to changing climate, land-use patterns, and fire suppression efforts. However, only a handful of studies have addressed the history of fire across the Oklahoma Cross Timbers landscape. This research adds to the body of literature by studying the contemporary forest structure and fire history at Lake Arcadia in Oklahoma County, Oklahoma. Results demonstrate that post oak ( Quercus stellata Wangenh.) and blackjack oak ( Q. marilandica Munchh.), two common species in Oklahoma Cross Timbers, dominate the forest. However, several mesophytic tree species are found in the overstory as well as the sapling layer of the forest. A total of 25 fire events (mean fire interval = 4.14 years) were documented during the 20 th century using fire-scar analysis of Q. stellata trees and remnant wood (stumps, snags, recently dead trees). High fire frequencies in the early to mid-20 th century corresponded to the recruitment of Q. stellata and Q. marilandica . Wet conditions (PDSI > 0) during the late 20 th century and no fires after 1985 corresponded to the recruitment of non-oak, mesophytic species at the study site. The results of this study suggest that changes in fire frequency and moisture availability are contributing to changes in tree density and species composition at the study site.